1. Field of the Invention
The present invention relates to transmission line members in which signal conductors transmitting high frequency signals of different frequencies are closely disposed, and to electronic apparatuses incorporating such transmission line members.
2. Description of the Related Art
Different kinds of transmission line members are developed for transmitting high frequency signals. For example, a transmission line member described in the specification of Japanese Patent No. 4962660 has a stripline structure. The transmission line member described in Japanese Patent No. 4962660 includes an elongated dielectric base body, and an elongated signal conductor is disposed at an intermediate point in the thickness direction of this dielectric base body. Ground conductors are disposed on both end surfaces in the thickness direction of the dielectric base body.
This allows the realization of a transmission line having a stripline structure in which a signal conductor is interposed between two ground conductors.
In a case that a plurality of such transmission line members configured as above is disposed inside a communication apparatus, in which transmission line members are to be installed, it is preferred to have a wider distance between the transmission line members.
However, with downsizing of electronic apparatuses, in some case, a plurality of transmission line members needs to be disposed close to each other. In this case, sometimes there is an issue in that adjacent transmission lines are electromagnetically coupled (high-frequency-wise coupling). This causes leakage of a first high frequency signal traveling a first transmission line to a second transmission line, allowing a leaked signal to travel on the second transmission line. Conversely, sometimes there is an issue in that a second high frequency signal traveling along the second transmission line leaks to the first transmission line, allowing a leaked signal to travel on the first transmission line.
To downsize the transmission line member, it is conceivable to have an example in which a plurality of signal conductors is disposed close to each other in a single dielectric base body. However, even in such a structure, there is a similar issue in that a plurality of transmission lines is likely to couple to each other. In other words, in such a case, noise is superimposed on a target high frequency signal, and transmission characteristics of the transmission line at which the noise is superimposed is degraded